Seminar ON SMART SENSOR Submitted by : SUBIR KUMAR GHOSH Roll No. IN-14/04 Electrical & Instrumentation Deptt. B.E 7th SemesterJORHAT ENGINEERING COLLEGE, JORHAT PIN: 785 007 (ASSAM)
CONTENTS Introduction Definition Usefulness of silicon technology in Smart Sensor Importance and Adoption of Smart Sensor General Architecture of Smart Sensor Block Level Design Consideration for Smart Sensor Summary of Different Smart Sensor Conclusions References
INTRODUCTION Main aim of Integrating the electronics and the Sensor is to make and intelligent sensor. Smart Sensor have the ability to take decision. Complete system is called a system on Chip. Smart Sensor consist of Transduction Element, Signal Conditioning Electronic and controller/processor.
DEFINITION Smart Sensors are sensors with Integrated Electronics that can perform the following functions : a) Logic Function b) Two way communication c) Make Decisions
Useful ness of Silicon Technology in Smart Sensor A smart sensor is made with same technology as Integrated circuits A transduction element either includes thin metal films, Zinc Oxide and Polymeric films
MECHANICAL SIGNAL DOMAIN Silicon Can be used for measuring force & pressure because of piezo-resistance effect By heating a silicon structure having two temperature devices and is brought to air flow then resulting the temperature difference is proportional to square root of flow velocity
THERMAL SIGNAL DOMAIN Electron devices in Silicon show temperature dependence this property of Silicon can be used for the measurement of Temperature We can measure temperature because seeback in Silicon is very large Magnetic Signal Domain• It can be used for the Construction of Hall Plates & Transistor Structure that are sensitive to magnetic field CHEMICAL Signal Domain* It can be used as humidity sensor or gas sensor
IMPORTANCE & ADOPTION OF SMART SENSOR The presence of controller in smart sensor has led to corrections for different undesirable sensor characteristics which include span variation , non –linearity, cross-sensitivity. REDUCE COST OF BULK CABLES & CONNECTORS By using smart sensor the cost of bulb cables and connectors is reduced REMOTE DIAGNOSTICS It is possible to have digital communication via a standard bus & a built in self-test. ENHANCEMENT OF APPLICATION Self Calibration – It means adjusting some parameters of sensor during fabrication this can be either gain or offset or both. Computation : Computation is also allows one to obtain the average, variance and standard deviation for the set of measurements. Communication : Communication is the means of exchanging or conveying information. Multi sensing : Some smart sensor has to measure more than one physical or chemical variable simultaneously SYSTEM RELIABILITY System reliability is significantly improved due to the utilization of smart sensor BETTER SIGNAL TO NOISE RATIO The electrical output of most sensors is very weak and it is transmitted through long wires lot of noise get coupled by using smart sensor this problem is avoided
ARCHITECTURE OF SMART SENSOR A general Architecture of smart sensor consist of following important components : Sensing element/transduction element Amplifier Sample and hold Analog multiplexer Analog to digital converter (ADC) Offset and temperature compensation Digital to analog converter (DAC) Memory 8Serial communication and processor
FUNCTIONS WITHIN ELECTRONICS Many a times it is required to alter the sensor excitation over the operating range of a SENSOR. an example of this is SILICON Wheatstone bridge, where the drive voltage is increased with increasing temperature ANALOG INPUT• Multiplexing of inputs can be done to avoid duplication of circuits in multiplexing inputs of same type and range are switched to a common front end. DATA CONVERSION* In case of Smart sensor most of the signal processing in digital form this is possible we have an ADC along with an Anti-aliasing filter.
SUMMARY OF DIFFERENT SMART SENSOR Optical Sensor• It is used for measuring exposure in cameras, optical angle encoders ACCELEROMETER* It consists of sensing element and electronics on SILICON INTREGATED MULTI SENSOR• This chip was fabricated using conventional Silicon planer processing, Silicon Micro machining and thin deposition technique.